Several grand challenges in energy storage and conversion involve the discovery functional materials which many agree will be multi-element solid solution of metal oxides. The conventional wet chemical methods for synthesis of multi-metal oxide often require time-consuming high pressure and temperature processes, and so the challenge is to develop rapid and scalable techniques with precise compositional control.

This presentation will discuss the concept of plasma oxidation of liquid precursors for making mixed metal oxides with compositional control and rapid time scales. The concept is demonstrated with binary, ternary and quaternary metal oxide with control over entire composition range using metal precursor solutions.¹ For the ternary system, the results show the selective formation of metastable spinel solid solution phases with compositions over the entire range by tuning the metal precursor composition.

The concept of plasma oxidation of liquid precursors is investigated to produce a number of materials systems for electrocatalysts, lithium ion batteries and heterogeneous catalysts. For example, in terms of oxygen evolution reaction, ternary alloys involving manganese doped nickel ferrite nanoparticles, NiMn_zFe_2-zO₄ (01), exhibited considerable electrocatalytic activity achieving an overpotential of 0.39V at a benchmarking current density of 10 mAcm^-2 for low manganese content at z = 0.2.¹ Lithiated NMC compounds exhibit about 220 mAh/g capacity after 50 cycles.

Acknowledgements

 The authors acknowledge support from NSF EPSCoR (1355438) and access to facilities at the Conn Center for Renewable Energy Research.

Reference

1. B.P. Ajayi, S. Kumari, D. Jaramillo-Cabanzo, J. Spurgeon, J. Jasinski and M.K. Sunkara, “A rapid and scalable method for making mixed metal oxide alloys for enabling accelerated materials discovery”, J. of Materials Research, DOI: http://dx.doi.org/10.1557/jmr.2016.9231 (11), 1596-1607(2016)